JSON

JSON, which is an acronym for Javascript Serializion Object Notation, is a data structure mostly associated with the web. It provides a dictionary like structure that is easily created, transmitted, read, and parsed.  Many coding languages include built in methods for these processes and it is largely used for transferring data and information between languages. For example, a web API on a server may be written in C# and the front-end application written in Javascript. The API request from Javascript may be serialized to JSON and then deserialized by the C# API. C# continues to process the request and responds with return data in JSON form. Python includes a JSON package aptly named json that makes the working with JSON and disctionaries easy. 

An example of JSON is: 

{ 
  "objectIdFieldName" : "OBJECTID",  
  "uniqueIdField" :  
  { 
    "name" : "OBJECTID",  
    "isSystemMaintained" : true 
  },  
  "globalIdFieldName" : "GlobalID",  
  "geometryType" : "esriGeometryPoint",  
  "spatialReference" : { 
    "wkid" : 102100,  
    "latestWkid" : 3857 
  },  
  "fields" : [ 
    { 
      "name" : "OBJECTID",  
      "type" : "esriFieldTypeOID",  
      "alias" : "OBJECTID",  
      "sqlType" : "sqlTypeOther",  
      "domain" : null,  
      "defaultValue" : null 
    },  
    { 
      "name" : "Acres",  
      "type" : "esriFieldTypeDouble",  
      "alias" : "Acres",  
      "sqlType" : "sqlTypeOther",  
      "domain" : null,  
      "defaultValue" : null 
    } 
  ],  
  "features" : [ 
    { 
      "attributes" : { 
        "OBJECTID" : 6,  
        "GlobalID" : "c4c4bcfd-ce86-4bc4-b9a2-ac7b75027e12",  
        "Contained" : "Yes",  
        "FireName" : "66",  
        "Responsibility" : "Local",  
        "DPA" : "LRA",  
        "StartDate" : 1684177800000,  
        "Status" : "Out",  
        "PercentContainment" : 50,  
        "Acres" : 127,  
        "InciWeb" : "https://www.fire.ca.gov/incidents/2023/5/15/66-fire",  
        "SocialMediaHyperlink" : "https://twitter.com/hashtag/66fire?src=hashtag_click",  
        "StartTime" : "1210",  
        "ImpactBLM" : "No",  
        "FireNotes" : "Threats exist to structures, critical infrastructure, and agricultural ands. High temperatures, and low humidity. Forward spread stopped. Resources continue to strengthen ontainment lines.",  
        "CameraLink" : null 
      },  
      "geometry" :  
      { 
        "x" : -12923377.992696606,  
        "y" : 3971158.6933410829 
      } 
    },  
    { 
      "attributes" : { 
        "OBJECTID" : 7,  
        "GlobalID" : "04772c32-acab-4f12-8875-7f456e21eda7",  
        "Contained" : "No",  
        "FireName" : "Ramona",  
        "Responsibility" : "LRA",  
        "DPA" : "Local",  
        "StartDate" : 1684789860000,  
        "Status" : "Out",  
        "PercentContainment" : 80,  
        "Acres" : 348,  
        "InciWeb" : "https://www.fire.ca.gov/incidents/2023/5/22/ramona-fire/",  
        "SocialMediaHyperlink" : "https://twitter.com/hashtag/ramonafire?src=hashtag_click",  
        "StartTime" : null,  
        "ImpactBLM" : "Possible",  
        "FireNotes" : "Minimal fire behavior observed. Resources continue to strengthen control ines and mop-up.",  
        "CameraLink" : "https://alertca.live/cam-console/2755" 
      },  
      "geometry" :  
      { 
        "x" : -13029408.882657332,  
        "y" : 4003241.0902095754 
      } 
    },  
    { 
      "attributes" : { 
        "OBJECTID" : 8,  
        "GlobalID" : "737be4e4-a127-486a-8481-a0ca62a631d7",  
        "Contained" : "Yes",  
        "FireName" : "Range",  
        "Responsibility" : "State",  
        "DPA" : "State",  
        "StartDate" : 1685925480000,  
        "Status" : "Out",  
        "PercentContainment" : 100,  
        "Acres" : 72,  
        "InciWeb" : "https://www.fire.ca.gov/incidents/2023/6/4/range-fire",  
        "SocialMediaHyperlink" : "https://twitter.com/hashtag/RangeFire?src=hashtag_click",  
        "StartTime" : null,  
        "ImpactBLM" : "No",  
        "FireNotes" : null,  
        "CameraLink" : "https://alertca.live/cam-console/2731" 
      },  
      "geometry" :  
      { 
        "x" : -13506333.475177869,  
        "y" : 4366169.4120039716 
      } 
    } 
] 
} 

Where the left side of the : is the property, and the right side is the value, much like the dictionary. It is important to note that while it looks like a python dictionary, JSON needs to be converted to a dictionary for it to be recognized as a dictionary and vice versa to JSON. One main difference between dictionaries and JSON is that JSON is that the properties (keys in Python) need to be strings whereas Python dictionary keys can be ints, floats, strings, Booleans or other immutable types.

Many API’s will transmit the requested data in JSON form and conversion is simple as using JSON.loads() to convert to JSON to a python dictionary and JSON.dumps() to convert it to a JSON object. We will be covering more details of this process in Lesson 2.